Photographic color reproduction process using colored couplers



Sept. 16, 1958 K. E. WHITMORE 0 PHOTOGRAPHIC COLOR REPRODUCTION PROCESS usmc COLORED COUPLERS Filed July 8. 1957 EXPOSURE /2 EMULSION CONTAIN/N6 COLORLESS MAGE/VM COUPLERA/VD Stage YELLOW COLORED COUPLER COLOR 3 H DEVELOPMENT \1 -/V-'/V-R2 gmnmmmmm Stage 2 DYE/N6 W/TH BASIC BLUE DYE I /3 YELLOW coup/.5? A/VD 51.115 DYE come-arm MASK Stage 3 KE/ TH E. WH/TMORE 1 NVEN TOR.

ATTORNEY & AGE/V7 United States Patent PHOTOGRAPHIC COLOR REPRODUCTION PROC- ESS USING COLORED. COUPLERS Keith E. Whitmore, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application July 8, 1957, Serial No. 670,409

12 Claims. (Cl. 96-9) This invention relates to color photography and particularly to color correction by incorporating in a silver halide emulsion a mixture of colored and uncolored couplers.

It is known that colored photographic images may be formed by using a developer which produces a colored compound on development. The colored compound thus formed is deposited adjacent the silver grains of the silver image during development. It is also known that a colored image may be formed by adding to certain developing solutions or by incorporating in the silver halide emulsion a compound which couples during development with the oxidation product of the developing agent and forms a colored compound which is likewise adjacent the silver grains of the silver image during development. Such a compound which is employed in conjunction with the developing agent for the silver and which couples with the oxidation product of the develop-. ing agent during development is referred to herein as a color-forming compound or coupler. v

In U. S. Patent No. 2,428,054, dated September 30, 1947, of P. W. Vittum et al., there is described a method for obtaining improved dye images by the use in the emulsion layer of a mixture of a colored coupler and a colorless coupler which produces dye images of the same hue upon coupling. Development of the exposed layer results in the color of the colored coupler being destroyed upon coupling, while at the same time the colorless coupler forms a dye image at the exposed regions. In this way, a masking efiect is achieved whereby undesired absorption, for example, in the blue spectral region is canceled out. However, it has been found that the choice of couplers is restricted and complete masking has not been possible. Also, the requirement of employing only those colored couplers which produce on development dyes of the same hue as the uncolored coupler seriously limits the application of this prior art process for many photographic materials and processes.

In my U. S. patent application Serial No. 470,499, filed November 22, 1954, now Patent No. 2,808,329, it has been shown that by the use in silver halide emulsions of a combination of certain colored couplers containing alkali-solubilizing groups, the dyes from which become soluble in the exposed areas on development and thereby permit complete removal by washing methods of the dye image thereof, with certain uncolored couplers that on development form insoluble dye images, some of the dis- 2,8523% Patented Sept. 16, 1958 mask with a normal dye image. In a reversal process wherein the exposed silver halide is developed with a silver-forming developer and the residual silver halide is then developed with a color-forming developer, the opposite relationship exists. The uncolored coupler forms a positive dye image and the colored coupler forms a negative dye image. The result is as before a color correction mask for the normal dye image. The choice of couplers determines the color of the positive image and also what wavelengths of light are transmitted through these images to the underlying silver halide emulsion layer or layers. Further advantages arise from the fact more silver halide is required in the system in order to produce the same amount of dye as is produced in the above-mentioned patent of P. W. Vittum et al. This kind of advantage can be better understood from a considera tion of the process of U. S. Patent No. 2,689,793, dated September 21, 1954, of W. R. Weller et al. Increasing the amount of silver halide used increases the emulsion speed and lowers the graininess of the dye image. That invention was, therefore, particularly adaptable to color photographic elements employing a plurality of super-. imposed silver halide emulsion layers wherein at least one layer or, if desired, all the layers contains a combination of at least one colored coupler and at least one uncolored coupler.

According to the present invention, in addition to providing a masking image composed of the uncoupled portion of the colored coupler containing sulfo or carboxy groups as described in my prior invention, the masking image is treated with a solution of a basic dye, preferably of a color diiferent from that of the residual colored coupler comprising the masking image. The result is to obtain a composite masking image of two dyes, that is, the residual colored coupler which is'a dye, and the dye mordanted thereto, which composite image compensates for substantially all of the unwanted light absorptions of the normal dye image in the emulsion layer.

In accordance with the invention, color photographic elements are prepared by coating in any order two or more differently sensitized silver halide emulsions, for example, sensitized to the blue, green and red, over one another and, if desired, separated by inert or colored gelatin layers, onto a suitable photographic support material such as films or sheets of cellulose acetate, cellulose mixed esters, cellulose nitrate, cellulose ether, synthetic resin materials such as polyesters, polyamides, etc., paper materials, glass plates, and the like. The preferred photographic color element contains three diiferently sensitized silver halide emulsion layers in the order of a bottom red-sensitized layer next to the support, a middle green-sensitized layer and a top blue-sensitized layer. Suitably colored couplers containing the alkali-solubilizing group may be used in any of the emulsion layers in conjunction with a colorless coupler, for example, a yellow colored coupler with a colorless magenta-forming coupler in the green-sensitive emulsion layer to which may be mordanted a blue dye or the same colored coupler in the red-sensitive layer for eventually mordanting a magenta dye thereto. As will be understood from more detailed description of my invention hereinafter, the colored couplers containing alkali-solubilizing groups will ordinarily be present in only one of the emulsion layers of a multilayer color film because of the difficulty of difierentially dyeing the residual coupler masking image present in different areas and strata of the color film.

colored coupler and a normal or negative image from the uncolored coupler. This results in a color correction However, those emulsion layers not containing the colored couplers of Formulas I and II hereinafter may aseasvo contain well-known colored couplers such as a yellow or magentacolored coupler which yields a cyan dye image in the exposed and color-developed areas.

The accompanying drawings show in greatly enlarged cross-sectional view a representation of a typical emulsion layer of a multilayer color film at three stages of preparing a composite masking image. In particular, the drawing illustrates the processing of a preferred embodiment, a green-sensitive emulsion layer usually interposed between redand blue-sensitive emulsions as mentioned above. As shown in stage 1 of the drawing, the element composed of the base layer it and emulsion ill containing a mixture of silver halide, colorless magenta coupler and yellow-colored pyrazolone coupler having the sulfonic acid group attached in a non-coupling position of the molecule, is exposed in area 12 and thereafter, as shown in stage 2, color development produces the magenta dye image in area 12 and at the same time since the yellow pyrazolone coupler splits at the azo linkage and couples with the color developing agent to form a dye which washes out of the layer, the residual yellow coupler remains in area 13. At this stage, the partial yellow mask compensates for only the blue absorption of the magenta dye image. Thereafter, as shown in stage 3, dyeing of the element of stage 2 with a basic blue dye results in mordanting of the blue dye to the sulfonic acid group of the residual yellow coupler image in area 13 to provide the composite correction mask composed of yellow coupler and blue dye compensating for both improper blue and red light adsorptions of the magenta image in area 12.

Suitable color couplers for use in the invention as described are disclosed in my prior invention aboveidentified and have the general formulas and CONHRi at least one sulfonic acid or carboxylic acid group. Ordinarily only one of the R groups contain the alkali-solubilizing group, and the preferred embodiment R or R contain the solubilizing group to allow selective removal of the coupler from the emulsion layer in the color developed areas. When the acidic group is attached to R color development forms an insoluble dye image in the exposed area of the emulsion layer. Compounds such as Nos. 1 to 21 of my prior invention possess the above structures and are very useful in the emulsion layers in conjunction with a suitable colorless coupler.

For illustration, compounds 1 and 7 have the following respective structures:

1-phenyl-3- 3-sulfobenzamido -4- (d-octadecyloxyphenylazo 5-pyrazolone 0 ounonionmno 0O 1 sons (Na) t N I] N II-CsHnOO C 1-hydroxy-4- (2-11-amylcarbonyl-3-naphthylazo -N- [B- 3-su1fobenzamido ethyl] -2-naphtharnide The following compound is similarly useful:

( S 0311 (Na) CsHn-t N=N CHzSOaH (Na) S 0 H (Na) which washes out of the emulsion layer.

These couplers may be used as follows:

Compound 22, for example, which is yellow-colored may be used to an advantage in an emulsion layer containing a colorless cyan-forming coupler. During color development of an emulsion layer thus constituted compound 22 splits at the azo linkage yielding the naphthol fragment which couples in the 4-position to yield a cyan dye image. The other fragment of the coupler split off during color development is a readily soluble azodye The residual unchanged coupler in the undeveloped portion of the emulsion layer may then be dyed up with a basic magenta dye such as Astraphloxine PP. The resulting masking image composed of the original magenta coupler and Astraphloxine dye thus compensates for the incorrect absorption of the cyan dye image in the green and blue regions of the spectrum.

Additional colored couplers useful in the invention in the manner described have the above structure I wherein R represents a p'henyl group, R; a m-sulfobenzamido group and R represents any one of the following groups:

The preparation of compounds having the Formulas I and 11 above are given in my prior invention identified above. Compound 22 is prepared as described in the Whitmore et al. U. S. patent application Serial No. 570,179, filed March 7, 1956, Example 3 thereof. Compounds 23 and 24 are prepared in a similar manner by diazo coupling of the appropriate 3-amido-5-pyrazolone with the desired aniline or naphthylamine derivatives.

Suitable colorless non-diffusing couplers for use in my invention in conjunction with the colored couplers in clude any of those described in U. S. Patent No. 2,298,443, October 13, 1942, of A. Weissberger, other well-known couplers will also be found to be useful in the process.

The following examples illustrate how the colored and colorless couplers may be employed in the practice of my invention to prepare color photographic elements having improved masking properties:

Example 1 0.10 part of coupler No. 1 above was moistened with ethyl alcohol and dissolved in just enough concentrated ammonium hydroxide solution to effect solution; 0.25 part of the colorless magenta-forming coupler l-(2',4',6'- trichlorophenyl)-3- [3 2',4"'-di-tert. amylphenoxyacetamido)-benzamido]-5-pyrazolone (Loria, U. S. Patent 2,600,788, June 17, 1952) was dissolved in 0.5 part of din-butylphthalstc. These two solutions, parts of a 10 percent aqueous gelatin solution and a dispersing agent were mixed together and then passed through a colloid mill. The mill was rinsed with 12 parts of Water and the rinse then added to the dispersion. Twelve parts of a bromoiodide emulsion were then added and the mixture stirred for 10 seconds. The resulting emulsion was then 6 coated on a film base in the usual manner. The resulting film was then exposed and developed in a color developing solution followed by washing, fixing and bleaching steps as described in Example 5 of my above-identified prior invention, or by means of the following steps carried out at 70 F.:

Develop minutes 9 Rinse seconds 5 Clear minutes 1 Wash do 3 Bleach d0 1 Rinse seconds 10 Fix minutes 1 Wash do 3 Dry.

The color developer for this process may have the following composition:

. Grams Sodium hex-ametaphosphate 1 2-amino-5-diethylaminotoluene hydrochloride 2 Sodium sulfite 2 Potassium bromide 2 Sodium carbonate 20 Water to 1 liter.

The bleach solution used in the process may be a solution of 50 grams of potassium ferricyanide and 20 grams of potassium bromide in 1 liter of water. A conventional hypo fixing bath may be used in the fixing step of the above process.

As a result of carrying out the above process, the emulsion contains a magenta dye image in the exposed area and a yellow masking image in the remaining area com:- posed of residual yellow-colored coupler, the dye formed from the split yellow coupler in the exposed area having washed out of the film.

Thereafter the film was bathed l to 5 minutes in a 1 millimolar solution of Methylene Blue dye at a pH of 9.0 followed by rinsing 2 to 5 minutes in 1 percent acetic acid solution. As a result, the final masking image was obtained composed of the residual yellow-colored coupler and the Methylene Blue dye mordanted thereto, as shown in stage 3 of the drawing which masking image tended to compensate for the improper blue and red light absorptions of the magenta dye image in the layer.

Example 2 Another coating was prepared in the manner of Example 1 except that 0.05 part of coupler l was used with 0.25 part of l-hydroxy-Z-[B-(2',4'-di-tert. amylphenoxy)- n-butylJ-naphthamide (Weissberger et a1. U. S. Patent 2,474,293, June 28, 1949). After processing as described in Example 1, the film containing a cyan dye image and ellow mask of residual coupler l was bathed with a 1.0 millimolar solution of the magenta dye Astraphloxine FF and rinsed briefly in dilute acetic acid solution. A composite mask was thus obtained in the film composed of residual yellow coupler l and the magenta dye mordanted thereto which compensated for blue and green light absorptions of the cyan dye image.

Additional examples of the preparation of masking images composed of residual colored coupler are provided by my prior invention identified above which masking images may be dyed with a basic dye of suitable color in the manner of Examples 1 and 2 above.

Typical basic dyes useful for dyeing the residual coupler masking image may be selected from the following:

Safranine O CI #841.

Quinaldine Red CI #808A.

Rosinduline 2B CI #829.

Astraphloxine FF Shultz and Lehmann #930. Rhoduline Blue CI #658.

7 Capri Blue CI #876. Brilliant Green CI #662. Malachite Green 'CI #657. Acrifiavin CI #790. Auramine CI #655. Flavinduline O CI #824. Methylene Blue CI #922.

It has also been found that the color correction of multilayer color films containing couplers may be effected in a manner similar to and if desired, in conjunction with that described above, by merely bathing a processed color film in a solution of a basic dye depending upon Whether or not the residual couplers in the respective emulsion layers are acidic. That is, many of the colorless couplers such as the phenolic hydroxyl coupler compounds are sufliciently acidic that when they are incorporated into silver halide emulsion layers and dye images are obtained therefrom, the residual coupler in the undeveloped areas will absorb sufiicient basic dye in preference to the dye image therefrom to provide an effective masking image in the emulsion layer. Basic dyes of the triphenyl methane, styryl and thiazine classes, for example, Crystal Violet, Pinaflavol and Methylene Blue have been found to be effective for this purpose.

Since it is sometimes desirable to effect a discriminatory absorption of the basic dyes in, for example, only the emulsion layers containing the yellow and magenta dye images, this can be accomplished in some instances by use of benzyl alcohol in the color developer with the result that some of the residual couplers will be found to absorb less basic dye than others. In addition, beuzyl alcohol can be used in the dye bath to obtain more complete and uniform absorption of the basic dye on the residual couplers.

The following procedure may be used for obtaining a discriminatory absorption of dyes in a color film: A multilayer color film is provided having colored colorforming couplers in some of the emulsion layers such as the Color Negative Film, Type 5248 described by Hanson and Kisner I. S. M. P. T. E. 61, 667-701 (1953) the red-sensitive emulsion layer containing an orangecolored coupler forming a cyan dye image such as disclosed in U. S. Patent 2,521,908 and if desired a colorless cyan-forming coupler, the green-sensitive emulsion layer containing the yellow coupler 1A above and in addition, if desired, a colorless coupler forming a magenta-colored image such as disclosed in U. S. Patent 2,600,788 and the blue-sensitive emulsion layer containing a colorless coupler forming a yellow dye image such as disclosed in U. S. Patent 2,298,443. The film is processed as described in the above publication through the color development, fixing, bleaching and final Washing steps with the result that the red-sensitive emulsion layer contains a cyan negative image and a positive orange colored residual coupler masking image, the blue-sensitive emulsion layer contains the yellow negative dye image and the green-sensitive emulsion layer contains a magenta negative image and a positive image of the residual yellow coupler 1A (the dye formed from coupler 1A in the color development step having been Washed out of the negative area). There after, the film is dyed throughout for five minutes in a 1.0 millimolar Methylene Blue solution pH 7.0, followed by rinsing in 28% acetic acid solution for five minutes or until the blue dye has been removed from all areas except where it is attached to the residual coupler 1A. After rinsing in water for one minute, the top layer of the film is then dyed selectively by controlled penetration methods with a 1.0 millimolar solution of Brilliant Red 46 dye pH 7.0 so as to absorb the red dye onto the residual yellow coupler in the blue-sensitive emulsion layer. Final rinse for two minutes in 1% acetic acid, Washing and drying yields a color negative having an orange positive masking image associated with the negative cyan image, a combined yellow dye and blue dye masking image associated with the negative magenta image and a red dye masking image in the yellow layer.

What I claim is:

1. The method of preparing a masking image in a multilayer photographic color film containing silver halide emulsion layers sensitized to light of different regions of the spectrum, one of which layers contains a colorless coupler which is reactive with the oxidation product of a primary aromatic amine developing agent to form a nondiffusible dye image in said layer and further contains a colored color-forming coupler of the class consisting of those having the following general formulas:

wherein R R and R each represent a member of the class consisting of an alkyl group and an aryl group, and R represents an aryl group, one of said groups having attached thereto a solubilizing group of the class consisting of a carboxylic acid group and a sulfonic acid group, which comprises developing colored images in said element from said colorless and colored couplers and simultaneously splitting said colored coupler at the azo group, thus forming a dye which is removed from the emulsion layer leaving the uncoupled portion of said colored coupler in the emulsion layer, and treating said uncoupled portion of colored coupler with a basic dye to form a colored mask in the emulsion layer composed of said colored coupler and said basic dye.

2. The process of claim 1 wherein the designated colored coupler of the photographic element has a solubilizing group attached to R 3. The process of claim 1 wherein the designated colored coupler of the photographic element has a solubilizing group attached to R 4. The process of claim 1 wherein the designated colored coupler of the photographic element has a solubilizing group attached to R 5. The process of claim 1 wherein the designated colored coupler of the photographic element has a solubilizing group attached to R by means of a second azo group.

6. The process of claim 1 wherein the colorless coupler is one forming an image of a color of the class consisting of cyan and magenta and the colored coupler is yellow in color.

7. The process of claim 1 wherein the colorless coupler is one forming a dye image of a color of the class consisting of cyan and magenta and the colored coupler is magenta in color.

8. The process of claim 1 wherein the colorless coupler is one forming a magenta dye image and the designated colored pyrazolone coupler I has the solubilizing group attached to R by means of a second azo group.

9. The process of claim 1 wherein the colorless coupler is one forming a cyan dye image and the designated colored naphthal coupler II has the solubilizing group attached to R by means of a second azo group.

10. The process of claim 1 wherein the colorless coupler is one forming a magenta dye image, the colored coupler is l-phenyl-3-(3-sulfobenzamido)-4-(4-octadecyloxyphenylazo)-5-pyrazolone and the basic dye principally absorbs red light.

11. The process of claim 1 wherein the colorless coupler is one forming a cyan dye image, the colored coupler is 1 phenyl 3-(3-sulfobenzamido)-4-(4-octadecy1- 10 oxyphenylazo)-5-pyrazolone and the basic dye principally absorbs green light.

12. The process of claim 1 wherein the colorless coupler is one forming a magenta dye image, the colored coupler is 1-phenyl-3-(3,5-disulfobenzamido)-4-(4-octadecyloxyphenylazo)-5-pyrazolone and the basic dye principally absorbs red light.

No references cited. 

1. THE METHOD OF PREPARING A MASKING IMAGE IN A MULTILAYER PHOTOGRAPHIC COLOR FILM CONTAINING SILVER HALIDE EMULSION LAYERS SENSITIZED TO LIGHT OF DIFFERENT REGIONS OF THE SPECTRUM, ONE OF WHICH LAYERS CONTAINS A COLORLESS COUPLER WHICH IS REACTIVE WITH THE OXIDATION PRODUCT OF A PRIMARY AROMATIC AMINE DEVELOPING AGENT TO FORM A NONDIFFUSIBLE DYE IMAGE IN SAID LAYER AND FURTHER CONTAINS A COLORED COLOR-FORMING COUPLER OF THE CLASS CONSISTING OF THOSE HAVING THE FOLLOWING GENERAL FORMULAS: 